Hi
To backup Personal Files you could burn to CD/DVD. If you have alot of files I would transfer them to a external Harddrive.
As far as making a backup of Vista itself. This may also backup your personal Data if you select that option:
http://www.acerpanam.com/synapse/dat...or%20%20DT.pdf
This may require many CD's or DVD's
As far as performance you will notice Xp is better and more stable (IMO)
Bill